Serena Williams ended what may have been big sister and "best friend in the world" Venus Williams' last great chance for an eighth major title to keep her own calendar grand slam bid on track.

The younger Williams prevailed 6-4 6-3 in the siblings' first Wimbledon meeting in six years to reach her 11th quarter-final at SW19.

The two five-time Wimbledon champions held nothing back on Centre Court, but Serena out-slugged her 35-year-old sister to sustain the dream of that elusive calendar slam.

The 33-year-old 20-time major champion summoned top form to shrug off any pangs of guilt at extending her own bid for a sixth Wimbledon crown at her sister's expense.

"It's hard to go up against someone you root for all the time no matter what, who you love and is your best friend in the world," said Serena.

"So it's never easy, but you just play for the competition and enjoy the moment.

"I think I served well today, I didn't hit huge serves, I hit one big serve and other than that I think I was really consistent with my serve.

"She was playing really well, but in the end I was able to come through."

Former Wimbledon champion Lindsay Davenport branded this the match everyone wants to see but cannot bear to watch in previewing the family battle of her fellow Americans.

Both sisters were able to suspend their inseparable bond long enough to throw everything at their respective bids for history however, creating an engaging and brutal contest.

Pure power: Serena Williams (Image: Action Images)

Serena's dominance was expected to be implicit - but her stubborn and committed big sister was anything but compliant.

Times were when accusations ran wild that domineering father Richard Williams would preordain the results of his daughters' meetings.

No longer, not with the head of the clan not seen at SW19 since 2012, to coincide with Serena gaining a level of independence through taking up with coach Patrick Mouratoglou.

The 45-year-old has overseen seven of Serena's 20 grand slam triumphs, further enhancing his already-burgeoning reputation.

Serena hailed Venus as the "pioneer" without whom she could never have dominated the history of the women's game, while praising her grit to withstand auto-immune condition Sjogren's syndrome and sustain her professional career.

Venus' last grand slam triumph came at Wimbledon in 2008: chances for the veteran to add to her seven crowns are now few and far between.

But when that ambition collided with Serena's bid to swipe all grand slam titles in one season, the younger Williams set sentiment aside to complete a hugely-impressive victory.

Venus fended off five break points as she battled to stay in the match in the second set, only to bow to her younger sister's raw power.

Waving to the crowd: Serena Williams (Image: Action Images)

Some 17 years after the pair's first professional meeting and six years on from their last Wimbledon battle, Serena blasted through to the last eight.

After sweeping to the Australian and French Open, Serena's Wimbledon form leaves her the justifiable title favourite.

"It definitely doesn't get easier, but today I was out there, I just thought 'wow I'm 33 and she's just turned 35 and I don't know how many more moments like this we'll have'," said Serena.

"I plan on playing for years but you just never know if we'll have an opportunity to face each other.

"So I just took the moment in, I thought 'we're at Wimbledon'.

"I remember when I was eight years old we dreamed of this moment, and it was kind of surreal for a minute there.

"It was really good to get it done in straight sets, put this behind me and just move forward."